Method of separating constituents of mineral oils



July 5, 1938. E. M. DONS El AL METHOD OF SEPARATING CONSTITUENTS OF MINERAL OILS Filed July 10, 1936 PA RA FFM/IC 5 0 L 77 cm MIXER 4 PA PA FFM/IC' .5 0 A u 770M IVAPHTHE/V/C SOLUTION SOLUTION m L M C Patented July 5, 1938 UNITED STATES PATENT OFFICE METHOD OF SEPARATING CONSTITUENTS OF MENERAL OILS Application July 10, 1936, Serial No. 89,922

4 Claims.

This invention relates to methods of separating constituents of mineral oils, and more particularly to the separation of parafiinic portions 7 from more naphthenic portions of the oils. The

invention is especially adapted for use with selective solvents in the separation of light and heavy constituents of the oils. The main object is to very effectively and economically separate such light and heavy constituents.

With the foregoing and other objects in view, the invention comprises the novel method hereinafter more specifically described and shown in the accompanying drawing, which illustrates one form of the invention. However, it is to be understood that the invention comprehends changes, variations and modifications within the scope of the claims hereuntoappended.

Fig. 1 is a diagrammatical view of a system embodying features of this invention.

Fig. 2 is an enlarged sectionon the line 2-2 in Fig. 1.

To illustrate one form of the invention we have shown a tank I for the oil stock to be separated, and a tank 2 for the selective solvent. Assuming that the oil is a lubricating oil stock to be separated into parafiinic and naphthenic fractions, the selective solvent may be of any suitable type. Excellent results can be obtained by using dichlorethyl ether as an extracting solvent, but any other desired solvent may be employed. Examples of such solvents are cresylic acid, nitrobenzene, furfural, etc.

A stream of oil stock is discharged from the tank I through a pipe 3 leading to a pipe 4, where the oil unites with a stream of solvent from a pipe 5. The mixed streams pass through a heater or cooler 6 to provide the desired temperature, and then to a mixer l which discharges into a separator 8 of any suitable type. In this separator the relatively heavy naphthenic portions of the oil settle to the bottom, while the lighter paraffinic portions rise to the top. A stream of paramnic solution is discharged through a pipe 9 and it may be distilled to recover the solvent, and otherwise treated in accordance with well understood methods.

The naphthenic solution is discharged through a pipe 10, and it is to be understood that this solution contains more or less of the valuable paraifinic fraction that can not be readily separated by the ordinary methods of settling. An object of the invention is to recover a substantial amount of the paraflinc oil that is ordinarily discharged in the naphthenic solution.

To illustrate this feature we have shown a settling chamber l l in the form of an upright cylindrical column, having an inlet pipe l2 near the middle, a discharge pipe l3 at the top for the light constituents, and a discharge pipe M at the bottom for the relatively heavy constituents.

The settling chamber may be provided with a circulating device including a pipe I5 leading to a pump l6 which discharges through a cooler IT to the inlet pipe 12. A mixer l2 may be located in the pipe l2. The pipe l may be connected to the pipe l2, so as to transmit the naphthenic solution to the circulating system. This stream of naphthenic solution merges into the cooled circulating stream, and the mixture passes into the settling chamber II.

To illustrate a suitable means for whirling the solution in the settling chamber II', we have shown the inlet pipe i2 at a tangent to said chamber. The whirling action is suggested by arrows in Fig. 2. It has a centrifugal action which separates the incoming solution into a relatively heavy naphthenic portion near the periphery of the chamber, and a lighter, more parafiinic portion near the center of said chamber. This separation is improved by cooling the incoming solution, and by circulating relatively naphthenic portions from the plane of the pipe l to the higher inlet pipe l2.

The whirling motion gradually decreases as the solution moves upwardly or downwardly from the plane of the inlet nozzle, so the advantage of settling is combined with the forcible separation due to the centrifugal action.

The relatively parafiinic portions of the solution gradually rise to the top of the settling chamber H and pass out through the pipe I3, while the more naphthenic portions gradually fall to the bottom and escape through the discharge pipe [4.

In the separation of wax-containing lubricating oil stocks, the relatively low temperature due to the cooler H, which may be about 60 F. to 7 0 F., will tend to solidify high melting point wax. Therefore, the upper portion of the settling chamber II is provided with a heating coil I8, which increases the temperature of the outgoing paraffinic solution. Another advantage of this heating operation lies in the fact that the paraflinic solution can be conveniently returned in a relatively warm condition through a pipe l9 to the pipe 4, which leads to the separator 8. The parafiinic solution from the settling chamber II is thus subjected to further extraction which removes additional naphthenic compounds therefrom. However, if desired, said paraflinic solution from the top of settling chamber ll may be discharged through a pipe 20, and then subjected to the usual refining operations.

We claim:

1. In the art of extracting constituents of mineral oils, the method of separting a solution of parafiinic and naphthenic compounds which comprises permitting the solution to settle in a chamber having an upper parafiinic settling zone and a lower naphthenic settling zone, discharging the resultant parafiinic liquid from the upper portion of the paraifinic settling zone, discharging more naphthenic liquid from the lower portion of the naphthenic zone, and introducing said solution into the liquid between said settling zones while forcibly whirling the incoming solution so as to centrifugally separate it into a relatively heavy liquid portion near the periphery of said settling chamber and a lighter more parafl'inic liquid portion near the center of said settling chamber. a

2. In the art of extracting constituents of waxcontaining mineral oils, the method of separating a solution of paraffinic and naphthenic compounds which comprises permitting the solution to settle in a chamber having an upper parafllnic settling zone and a lower naphthenic: settling zone, discharging the resultant wax-containing paraffinic liquid from the upper portion of the paraffinic settling zone, discharging more naphthenic liquid from the lower portion of the naphthenie zone, and introducing said solution into the liquid between said settling zones While forcibly whirling the incoming solution so .as to centrifugally separate it into a relatively heavy liquid portion near the periphery of said settling chamber and a lighter wax-containing parafiinic liquid portion near the center of said settling chamber.

3. In the art of extracting constituents of waxcontaining mineral oils, the method of separating a solution. of paraflinic and naphthenic compounds which comprises cooling said solution, permitting the cooled solution to settle in a chamber having an upper paraflinic settling zone and a lower naphthenic settling zone, discharging the relatively paraffinic liquid from said paraflinic settling zone, discharging more naphthenic liquid from the lower portion of the naphthenic zone, and introducing said solution into the liquid between said settling zones while forcibly whirling the incoming solution so as to centrifugally separate it into a relatively heavy liquid portion near the periphery of said settling chamber and a lighter wax-containing liquid portion near the center of said settling chamber.

4. In the art of extracting constituents of mineral oils, the method of separating a solution of parafiinic and naphthenic compounds which comprises permitting the solution to settle in a chamber having an upper paraffinic settling zone and a lower naphthenic settling zone, discharging the resultant paraifinic liquid from the upper portion of the paraflinic settling zone, discharging more naphthenic liquid from the lower portion of the naphthenic zone, withdrawing liquid from said naphthenic settling zone and forcibly discharging the withdrawn liquid into the liquid between said settling zones, in a tangential direction, so as to centrifugally separate it into a relatively heavy liquid portion near the periphery of said settling chamber and a lighter more paractfinic liquid portion near the center of said settling chamber.

EDDIE M. DONS. OSWALD G. MAURO. DWIGHT B. MAPES. 

